In order to overcome the shortcomings of a single commuting mode, eight VOCs including benzene, toluene, xylene, ethylbenzene, styrene, formaldehyde, acetaldehyde, and acrolein were studied in five commuting modes in Guangzhou. Applying the Monte Carlo simulation method, we assessed the health risk of these VOCs in five commuting modes, cars, air-conditioned buses, non-air-conditioned buses, subways, and bicycles, and analyzed the sensitivity of each exposure parameter. We used Crystal Ball 11.1 with 10000 iterations of independent runs and 95% confidence interval. The results show that the commuters of air-conditioned buses and cars are subjected to a higher cancer risk, following the t-distribution and lognormal distribution with 1.65×10-5±5.74×10-9 and 5.01×10-6±3.56×10-11, with the probability of exceeding 10-6 of 97% and 74.85%, respectively. The cancer risks of bicycles, non-air-conditioned buses, and subways are smaller, but their averages are higher than 10-6. The commuters of cars and air-conditioned buses were subjected to a larger non-cancer risk, following the lognormal distribution of 2.51±2.74 and 1.20±1.36; the contributions of acrolein are above 80%. The non-cancer risk of bicycles is the smallest and will not be a threat to human health. Sensitivity analysis shows that the sensitivities of ET, CA, ED, IR, and EF are larger, with the values of 55.5%, 32%, 10.5%, 1.1%, 0.2%, respectively, and BW has negative sensitivity.
